Dengue is a viral disease caused by the dengue virus (DENV), which is transmitted to humans primarily through the bites of infected Aedes mosquitoes. It is considered one of the most important arboviral diseases worldwide, with a significant impact on public health. This comprehensive overview will cover the epidemiology of Dengue, including global prevalence, transmission routes, affected populations, key statistics, historical context, major risk factors, and impact on different regions and demographics.
Global Prevalence: Dengue is endemic in more than 100 countries, mainly in tropical and subtropical regions. According to the World Health Organization (WHO), approximately 3.9 billion people in 128 countries are at risk of contracting Dengue. It is estimated that there are around 390 million Dengue infections per year, of which 96 million manifest clinically. The disease has seen a significant increase in incidence over the past few decades, with a tenfold rise in reported cases since the 1960s.
Transmission Routes: Dengue is primarily transmitted through the bites of infected female Aedes mosquitoes, predominantly Aedes aegypti and, to a lesser extent, Aedes albopictus. These mosquitoes are most active during the day, particularly during early morning and late afternoon periods. Additionally, the virus can be transmitted vertically from an infected mother to her fetus and through blood transfusion or organ transplantation.
Affected Populations: Dengue can affect individuals of all ages and both sexes. However, certain populations are more vulnerable to the severe forms of the disease, such as infants, young children, and individuals who have previously been infected with a different serotype of the virus. People living in urban and semi-urban areas with inadequate sanitation and limited access to clean water are at higher risk due to the favorable breeding environments for Aedes mosquitoes.
Key Statistics: - Dengue is responsible for an estimated 10,000 deaths annually, with the majority being severe cases. - The disease is responsible for a significant burden on healthcare systems, with an estimated annual cost of around US$8.9 billion. - There are four distinct serotypes of the dengue virus (DENV-1, DENV-2, DENV-3, and DENV-4), and infection with one serotype does not provide long-lasting immunity against the others, which increases the risk of severe forms of the disease upon subsequent infections.
Historical Context and Discovery: The history of Dengue can be traced back to ancient times, with descriptions of its symptoms similar to those seen today. The term "Dengue" originated from the Swahili phrase "ka-dinga pepo," meaning "cramp-like seizure caused by an evil spirit." The first recorded pandemic occurred in 1779-1780, affecting Asia, Africa, and North America. However, the virus responsible for Dengue was not identified until 1943 when it was isolated in the blood of a febrile patient during an outbreak in the Philippines.
Major Risk Factors: - Urbanization and population growth: Increasing urbanization and population density provide favorable conditions for the breeding and spread of Aedes mosquitoes, increasing the risk of Dengue transmission. - Climate change: Changes in temperature and rainfall patterns can influence the distribution and abundance of Aedes mosquitoes, potentially expanding the geographic range of Dengue. - Inadequate vector control measures: Inadequate mosquito control programs, including ineffective insecticide usage and lack of community participation, contribute to the persistence and spread of Dengue. - Travel and globalization: Increased international travel and trade facilitate the introduction and spread of Dengue to new regions. - Socioeconomic factors: Poverty, inadequate housing, and limited access to healthcare contribute to the vulnerability of certain populations to Dengue.
Impact on Different Regions and Populations: The impact of Dengue varies across different regions and populations. Southeast Asia and the Western Pacific region bear the highest burden, accounting for approximately 75% of global Dengue cases. However, the disease is also endemic in the Americas, Africa, and the Eastern Mediterranean. The severity and prevalence rates can vary within countries, with urban areas often experiencing higher transmission rates than rural areas. Additionally, children and young adults tend to be more affected, while severe forms of the disease are more common among older adults who have previously been infected with a different serotype.
In conclusion, Dengue is a significant global health issue with a high prevalence in tropical and subtropical regions. Its transmission primarily occurs through the bites of infected Aedes mosquitoes, with various risk factors influencing its spread. The disease affects individuals of all ages, but certain populations, including infants, young children, and those with previous infections, are at higher risk of severe forms of the disease. Dengue's impact varies across regions, with Southeast Asia and the Western Pacific region experiencing the highest burden. Effective vector control measures, improved healthcare access, and public awareness are crucial in reducing the impact of Dengue worldwide.

Download Data(下载数据)

Seasonal Patterns:
- From the data, we can observe a consistent seasonal pattern for Dengue cases in mainland China. The number of cases tends to increase from June to September, which corresponds to the summer months.
Peak and Trough Periods:
- The peak period for Dengue cases in mainland China occurs during the months of September and October. During these months, the number of cases reaches its highest level. On the other hand, the trough period, or the period with the lowest number of cases, occurs from December to February.
Overall Trends:
- Over the years, there is an overall increasing trend in Dengue cases in mainland China, especially in recent years. The number of cases has significantly risen since 2014, with continued increases through 2019. However, there is a notable decrease in cases from 2020 onwards.
- The seasonal pattern of Dengue cases in mainland China suggests a strong association with weather conditions, particularly the warmer months. This is commonly observed in many regions where Dengue is prevalent.
- The peak period in September and October can be attributed to various factors, including higher mosquito activity, increased human exposure to mosquitoes, and potentially higher Dengue virus transmission rates during this time.
- The overall increasing trend in Dengue cases from 2014 to 2019 indicates a potential worsening of the Dengue situation in mainland China during this period. Factors such as population growth, urbanization, and climate change may have contributed to the rise in cases.
- The decrease in cases from 2020 onwards could be influenced by various factors, including improved disease surveillance, vector control measures, and public health interventions. However, further analysis and investigation are needed to understand the exact reasons behind this decline.
- It's important to note that the data provided only includes information on Dengue cases and deaths. To fully understand the Dengue situation in mainland China, additional data on factors such as mosquito populations, environmental conditions, and preventive measures would be valuable.
- Overall, the analysis suggests a seasonal pattern with peak periods in September and October, an overall increasing trend in Dengue cases until 2019, and a recent decline in cases since 2020. These findings highlight the need for continued surveillance, prevention, and control measures to manage the Dengue burden in mainland China.